Road working machines



Dec. 19, 1961 F. c. WEST 3,013,552

ROAD WORKING MACHINES Filed Nov. 13, 1958 F/GJ. 37 5/ z s 36/34 3295o 32 /4/5 I -39 UllllllillllllllllllHllllIIIIIIIHHH Inventor L'AJQ M W States This invention relates to road working machines, and is concerned more specifically with road heaters forming part of, or for use with, road planing machines.

The modern method of levelling, repairing and renewing bituminous road surfaces is to heat the surface so as to soften the bitumen, and to remove all or part of the surfacing material by planing. For heating the road surface, it is usual to employ a heater comprising a cowl beneath which are arranged a burner or burners, for example, oil burners. The burners are disposed so that the flame is directed beneath the cowl on to or over the road surface, the cowl serving as .a furnace combustion chamber and also to reflect heat downwards.

One of the problems associatedwith the operation of such road heaters is the creation of large volumes of smoke. The bituminous road surfacing material frequently contains constituents which are readily volatilized on heating, giving off gases and vapours, mostly inflammable, which tend to promote the release of dense clouds. of smoke. It is an object of the invention to provide a road heaterin which the smoke problem is overcome or considerably reduced.

It is a further object to afford a method of heating a bituminous road surface in preparation for road planing, comprising moving a furnace cowl slowly forward over the road surface close thereto while directing the flame from a burner or burners into the furnace space beneath the cowl, and at the same time spraying into the cowl suflicient of a fire-inhibiting liquid to abate smoke;

According to another object of the invention, in a road heater of the kind having a cowl to travel over the road surface and a burner or burners for heating the road surface beneath the cowl, spray orifices or jets are provided to enable a fire-inhibiting liquid to be sprayed underneath the cowl. The liquid may be one of the known solutions used for fire-proofing; examples of these are ammonium phosphate, ammonium sulphate, ammonium chloride, boric acid and various silicates. Preferably, however, the liquid is a novel solution of the kind hereinafter to be described.

One arrangement according to the invention, will now be described by way of example, reference being had to the accompanying diagrammatic drawings in which:

FIGURE 1 is a side elevation, and

FIGURE 2 isa plan- 5. Referring firstly to FIGURE 1 the road heating appliance shown has a cowl 11 for travel over the ground which cowl is substantially rectangular in plan and in transverse cross-section. It has twin burners 12 to project flame into it through its rear end wall 13, in a direction forward and obliquely downward as shown so that the flame strikes and spreads over the road surface. It also has a chimney 14 rising from its roof 15 near the front end 16, the chimney being situated beyond the end of the flame which the burners are designed to project.

The two side walls of the cowl terminate at the bottom in skids or sled-type runners 18 which, when the heater is in use, rest on the road surface. The front wall 16 is provided along its bottom edge with a gate plate 21, which closes a gap between the lower edge of wall 16 and the road surface. The gate plate 21 has a forwardly-projecting portion or flange 22 in contact with the road,

which flange has an upturned nose 23 enabling it to ride over any normal obstruction on the road surface.

The cowl 11 is pivotally suspended from the outer end of a jib 28 projecting from the vehicle which carries it. This vehicle will normally be a road planing machine. Such machines are well known in the art, and, apart from the ensuing description of the manner of suspension of the heating cowl, it is not necessary to give details of this machine. The jib 28 is pivotally mounted or fulcrumed, at a point 29 intermediate its ends, on' the vehicle chassis 3t), and its inner end engages the lower end of an hydraulic ram 31 mounted in a yoke 27. The inner end of the jib is also'urged downwards by a coil spring 32 surrounding the ram and having an adjustable abutment. The spring 32 is designed so as to counterbalance the cowl 11 to such an extent that when the cowl is in contact with the road surface it presses thereon with only a small fraction of its weight.

In the working position, the cowl is maintained lightly 29 away from the ram 31. When the obstruction iscleared, the cowl descends under gravity into contact with the ground, its descent being braked by the spring 32.

When the cowl 11 is to be raised from the road deliberately, this is done by means of the ram 31. When the machine is travelling, it is undesirable that the-load of the cowl be taken primarily by the ram. It is for this reason that the abutment of the spring is adjustable, adustment allowing the load to be taken by the spring.

It is frequently necessary that the cowl be caused to travel close alongside a kerb. It is not always easy to do this by adjusting the position of the travelling vehicle as a whole. For this reason the cowl is adjustably mounted so it can be offset laterally from the centre-lineof the machine to a limited extent.

As seen in FIGURE 2, the jib 28 comprises a pair of arms 36 which converge rearwardly away from the cowl 11, and are united at their front and rear ends by crossmembers 37, 38'. A bracket 39 on the rear end of, the

. jib 28 extends beneath the cowl-elevating ram 31 in the yoke 27 on the chassis-3tl of the road-planing machine or other vehicle bearing the cowl. The jib is arranged to pivot horizontally at its rear end about the ram axis 42,

and also to rock vertically on pivotbearings 43 inter mediate its length, which pivot bearings'are disposed at the point 29 already mentioned. The pivot bearings 43;

zontal plane about the mid-point 47 of the front cross member 37 of the jib 28, additional support to the cowl being afforded by pin-and-slot connections 48 at opposite ends of the jib member 37.

By the two horizontal pivotal movements, the cowl can, therefore, be displaced into laterally off-set positions all parallel to each other. To effect these two pivotal movements a pair of jacks 50 are provided on the chassis 30 to thrust the jib 28 into the desired laterally-displaced positions, and another pair of jacks 51 are provided at the front end of the jib 28 to turn the cowl 11 into the desired horizontally-adjusted positions. The jacks of each pair act in opposite directions on the jib and cowl respectively and may serve to hold them in their adjusted positions. The rods of the jacks 51 act on a cross mem- Patented Dec. 19," 1961 3 her on the cowl top while the rods of the jacks 50 act on the opposite ends of the cross beam 44.

By reason of the relatively close contact of the sides of the cowl with the road surface, the chimney is made to discharge combustion and other gases at a point well above working level while ensuring appropriate combustion conditions inside the cowl.

Two spray units 41, each similar in character to a low pressure fuel burner, are provided at the front end of the cowl more or less at the opposite front corners and low down almost at road level on the flange of the gate plate 21 to spray a fire-proofing solution underneath the cowl. The spray units are adjusted so as to direct the liquid sprays rearwardly through the gate plate 21 toward the flame produced by the oil burners 12 and also somewhat inwardly toward one another, as shown, so as to treat substantially the whole Width of the space in the cowl. If desired, the sprays may be directed downwardly toward the road surface, but it is found that the best results are achieved if the sprays play toward the flame spaces.

The fire-proofing solution may be a roughly one part in 80 solution of ammonium phosphate, but is preferably a solution of a novel kind which will now be described. The novel solution comprises calcium silicate in a solution of sodium silicate and sodium carbonate. This may be formed by adding insuflicient calcium chloride to react with the whole of a sodium silicate solution.

As an example, a solution can be made up substantially in the proportions, per 100 gallons of concentrated fluid, of 60 lbs. calcium chloride, 90 lbs. of sodium silicate and 100 lbs. sodium carbonate. This results in a concentrated fluid which gives reasonably stable storage, and is diluted before actual use in the range of 30:1 to 50:1.

The solution is fed to the sprays 41 by gravity from a tank (not shown) on the road planing machine through pipes 40, and the sprays have atomizers which are operated by an air supply, say at 3 lbs. per square inch, also provided from the planing machine through pipes 26. The pipes extend from the planing machine and round the outside of the cowl to the front gate plate 22 thereon.

The rate of spraying of the liquid should be related to the size of the cowl and the speed of its travel, and it has been found that a gallon of spray to each to 15 square yards of road surface usually gives best results. The amount, however, varies with the nature of the surface and in some cases can be down to 1 gallon to squareyards.

With the arrangement described, a striking transformation is observed from conditions of heavy black smoke without the sprays to clean combustion when the sprays are in use. The result is not achieved simply by cooling the road surface, since the penetration of the heat into the road surface, and hence the cutting speed of the planing machine, are but little affected.

It will be understood that modifications of the above described arrangement. are possible without departing from the scope of the invention. Thus, the spray units need not be disposed at the front corners of the cowl but can occupy other positions.

I claim:

1. A method of heating a bituminous road surface in preparation for road planing, comprising moving a furnace cowl slowly forwardly over the road surface close thereto while directing flame from at least one burner into the furnace space beneath the cowl and over the road surface, and at the same time spraying continuously into said furnace space in a direction toward the flame and in sufficient quantity to abate smoke a liquid medium comprising calcium silicate formed in a solution of sodium silicate and sodium carbonate by adding calcium chloride in quantity insuflicient to react with the whole of the sodium silicate.

2. A method of heating a bituminous road surface in preparation for road planing, comprising moving a furnace cowl slowly forwardly over the road surface close thereto while directing flame from at least one burner into the furnace space beneath the cowl and over the road surface, and at the same time spraying continuously into said furnace space in a direction toward the flame and in sufficient quantity to abate smoke a liquid medium previously prepared by mixing calcium chloride, sodium silicate and sodium carbonate substantially in the proportions of lbs. calcium chloride, lbs. sodium silicate and lbs. sodium carbonate per 100 gallons of concentrated fiuid said concentrated fluid being diluted in the range 30:1 to 50: 1.

3. A method of heating a bituminous road surface in preparation for road planing, comprising moving a furnace cowl slowly forwardly over the road surface close thereto while projecting flame from at least one burner into the furnace space beneath the cowl from the rear end of the cowl, considered in the direction of travel, said flame being directed forwardly and obliquely downward so that the flame strikes and spreads over the road surface, and at the same time spraying continuously into said furnace space from at least one location low down near the road surface at the front end of the cowl and in a rearward direction toward the flame a liquid medium previously prepared by mixing calcium chloride, sodium silicate and sodium carbonate substantially in the proportions of 60 lbs. calcium chloride, 90 lbs. sodium silicate and 100 lbs. sodium. carbonate per 100 gallons of concentrated fluid said concentrated fluid being diluted in the range 30:1 to 50:1, the spray rate being in the order of 1 gallon for 10 to 15 square yards of road surface.

References (Iited in the file of this patent UNITED STATES PATENTS 814,550 Lewis Mar. 6, 1906 1,062,655 Macleod May 27, 1913 1,629,044 Morter May 17, 1927 2,273,254 Davis Feb. 17, 1942 FOREIGN PATENTS 210,581 Great Britain Feb. 7, 1924 444,745 Great Britain Mar. 25, 1936 

